1. Field
An embodiment of this invention relates to a head used in a disk device such as a magnetic disk device, a head suspension assembly provided with the head, and a disk device provided with the head suspension assembly.
2. Description of the Related Art
A disk device, e.g., a magnetic disk device, includes a magnetic disk, spindle motor, magnetic head, and carriage assembly. The magnetic disk is disposed in a case. The spindle motor supports and rotates the disk. The magnetic head writes and reads information to and from the disk. The carriage assembly supports the magnetic head for movement with respect to the magnetic disk. The carriage assembly includes a rockably supported arm and a suspension extending from the arm. The magnetic head is supported on an extended end of the suspension. The head includes a slider attached to the suspension and a head portion on the slider. The head portion is constructed including a reproducing element for reading and a recording element for writing.
The slider has a facing surface that is opposed to a recording surface of the magnetic disk. A predetermined head load directed to a magnetic recording layer of the disk is applied to the slider by the suspension. When the magnetic disk device operates, an airflow is generated between the disk in rotation and the slider. Based on the principle of aerodynamic lubrication, a force (positive pressure) to fly the slider above the recording surface of the disk acts on the facing surface of the slider. By balancing this flying force with the head load, the slider is flown with a given gap above the recording surface of the disk.
The flying height and posture of the slider are expected to be substantially fixed without regard to the radial position of the magnetic disk. The rotational frequency of the disk is constant, while its peripheral speed varies depending on the radial position. Since the magnetic head is positioned by the rotary carriage assembly, moreover, a skew angle (angle between the direction of the flow and the center line of the slider) also varies depending on the radial position of the disk. In designing the slider, therefore, changes of the flying height and posture based on the radial position of the disk, e.g., the fluctuation of the pitch angle, must be suppressed by suitably utilizing the aforesaid two parameters that vary depending on the radial position of the disk. For example, the positive pressure generated in the slider varies between the inner and outer peripheral portions of the magnetic disk, so that the pitch angle of the slider fluctuates easily.
There is known a disk device in which a negative-pressure cavity is formed near the center of a facing surface of a slider in order to prevent such fluctuations of the flying height and posture (e.g., Jpn. Pat. Appln. KOKAI Publication No. 2001-283549). Proposed in Jpn. Pat. Appln. KOKAI Publication No. 2001-312811, moreover, is a recessed leading pad that is provided on a facing surface of a slider.
With the magnetic head of the disk devices described above, however, it is hard to fully reduce the pitch angle fluctuation between the inner and outer peripheral portions of the magnetic disk, and a fluctuation of tens of percent occurs. If the flying behavior of the magnetic head changes in this manner, recording and reproduction may possibly fail to be stabilized. Thus, the device lacks in reliability.